[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 250004
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
804 PM EDT Sat Mar 24 2018

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South America,
and Atlantic Ocean to the African coast from the Equator to 32N.
The following information is based on satellite imagery, weather
observations, radar and meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through
2300 UTC.

...SPECIAL FEATURES...

...GALE WARNING FOR THE SOUTH-CENTRAL CARIBBEAN SEA...

A combination of strong surface high pressure ridging southward
along the U.S. east coast and relatively strong low pressure over
northern South America supports winds to gale force near the coast
of Colombia. The gale force winds will not be continuous but are
expected to recur each night during the evening and overnight
hours through the end of next week while this surface weather
pattern persists. The next gale is forecast to commence at 00Z
this evening over the area from 11N to 12N between 74W and 76W,
with corresponding seas of 9 to 12 ft. For more details please see
High Seas Forecasts issued by the National Weather Service under
AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC. This information can also
be found at the following website:
www.nhc.noaa.gov/marine

...GALE WARNING for the METEO-FRANCE areas...

Please refer to the METEO-FRANCE High Seas Forecast, that is
listed on the website: WWW.METEOFRANCE.COM/PREVISIONS-METEO-
MARINE/BULLETIN/GRANDLARGE/METAREA2. Gale-force winds N to NE
winds are forecast to develop this evening for the following
areas: Portions of the AGADIR and TARFAYA zones adjacent to the
coast of Morocco. The gales are expected to continue for the next
days or so until Sun evening. Winds will become strong northerly
Sun night through Mon night.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from Sierra Leone on the African coast
near 08N13W to 04N19W. The ITCZ continues from 04N19W to 01N30W
to the northeast coast of Brazil near 02S45W. Scattered moderate
and isolated strong convection is present within an area bounded
by 01S05W to 03N32W to 06N11W to 01S05W.


...DISCUSSION...

GULF OF MEXICO...

Fair weather prevails across the entire Gulf of Mexico as 1023 mb
surface high pressure centered off the Atlantic coast of N
Florida near 29N78W ridges westward across the Gulf. Abundant dry
air prevails as ridging at the mid and upper levels of the
atmosphere extends over the Gulf. Moderate to fresh E to SE
surface winds are noted over the eastern and central Gulf, while
SE to S winds are observed over the western Gulf. Sea heights are
highest, near 7 ft, in the NW Gulf due to the longer fetch there.
The area of surface high pressure is expected to gradually shift
ESE during the next several day. The high will be reinforced by
stronger ridging building S along the E coast of the United
States. Developing low pres over the central plains states will
tighten the pressure gradient over the Gulf and cause winds to
become fresh to strong on Tue. Surface troughing is expected to
develop over the Yucatan Peninsula each day, then migrate W into
the Bay of Campeche during the evening and nighttime hours.
Otherwise, fair weather is expected to continue through the
weekend as dry air remains in place.

CARIBBEAN SEA...

Undersea volcano Kick'em Jenny, north of Grenada near 12.18N
61.38W, is in a state of unrest. The government of Grenada advises
mariners to observe a 5 km or 3.1 nm exclusion zone around
Kick'em Jenny. Please refer to the web page, www.nadma.gd, for
additional information.

Relatively quiet conditions exist across the Caribbean Sea as
mid- to upper-level ridging maintains a relatively dry and
subsident weather pattern over the basin. Trade winds are
strongest over the south-central waters N of the coast of
Colombia. Winds are expected to reach gale force during the
evening and overnight hours through Thu night and Fri morning. See
the SPECIAL FEATURES section above for more details. Otherwise,
ridging extending southward from along the east coast of the
united States will maintain moderate to fresh NE to E winds over
the Caribbean basin through the first half of next week.

ATLANTIC OCEAN...

A slow moving cold front enters the discussion area near 32N54W
and continues southwestward to Puerto Rico. Another cold front
extends SW from 32N58W to 27N63W. This front is beginning to
weaken and will merge with and reinforce the first cold front.
Scattered showers and isolated thunderstorms are observed along
and up to 120 nm SE of the first front N of 26N. The second front
has little convection associated with it. West of these fronts,
surface high pressure dominates the area with NW to NE flow and
cooler air covering the western Atlantic. Expansive surface high
pressure dominates the central and eastern Atlantic Ocean. A
strong 1032 mb high is centered over the E Atlantic just SW of the
Azores near 36N30W with a ridge extending WSW to NE of the
Leeward Islands near 22N57W. This high is producing moderate to
fresh trade winds across a large portion of the tropical and
subtropical eastern Atlantic waters N of the ITCZ and W of 25W.

The fronts currently over the west-central Atlantic are expected
to merge and slowly shift eastward, then weaken. Another cold
front will enter the far northwestern waters late Sun through Mon
in conjunction with developing low pres SE of New England.

For additional information please visit
http://www.hurricanes.gov/marine

$$
McElroy
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